1. Field of the Invention
The present invention relates generally to microscopy and photography, and in particular, to differential interference contrast (DIC) microscopy and photography based on wavefront sensors.
2. Description of the Related Art
(Note: This application references a number of different publications as indicated throughout the specification by reference numbers enclosed in brackets, e.g., [x]. A list of these different publications ordered according to these reference numbers can be found below in the section entitled “References.” Each of these publications is incorporated by reference herein.)
Differential interference contrast (DIC) microscopy renders excellent contrast for optically transparent biological samples without the need to introduce any exogenous contrast agents into the samples. Due to this noninvasive nature, DIC microscopes are widely used in biology laboratories. However, the conventional DIC technique has several limitations. One major disadvantage is that the conventional DIC microscope translates phase variations into amplitude (intensity) variations, and therefore phase variations cannot be easily disentangled from amplitude variations that arise from sample absorption and/or scattering [1]. In other words, conventional DIC microscopes are inherently qualitative as a consequence of nonlinear phase gradient response and entanglement of amplitude and phase information. In addition, conventional DIC images of birefringent samples can have significant artifacts as the conventional DIC microscope depends on polarized light and uses polarization in its phase imaging strategy.